A plasma display panel (hereinafter referred to as “PDP” or “panel”) is a display device that has a large screen, is thin and light, and has high visibility.
A typical alternating-current surface discharge type panel used as the PDP has many discharge cells between a front plate and a back plate that are faced to each other. The front plate has the following elements:                a plurality of pairs of display electrodes disposed in parallel on a front glass substrate; and        a dielectric layer and a protective layer for covering the display electrodes.Here, each display electrode is formed of a scan electrode and a sustain electrode. The back plate has the following elements:        a plurality of data electrodes disposed in parallel on a back glass substrate;        a dielectric layer for covering the data electrodes;        a plurality of barrier ribs disposed on the dielectric layer in parallel with the data electrodes; and        phosphor layers disposed on the surface of the dielectric layer and on side surfaces of the barrier ribs.The front plate and back plate are faced to each other so that the display electrodes and the data electrodes three-dimensionally intersect, and are sealed. Discharge gas is filled into a discharge space in the sealed product. In the panel having this configuration, ultraviolet rays are emitted by gas discharge in each discharge cell. The ultraviolet rays excite respective phosphors of red (R), green (G), and blue (B), emit light, and thus provide color display.        
A subfield method is generally used as a method of driving the panel. In this method, one field time period is divided into a plurality of subfields, and the subfields at which light is emitted are combined, thereby performing gradation display. Here, each subfield has an initialization time period, a writing time period, and a sustaining time period.
In the initialization time period, initializing discharge is performed simultaneously in all discharge cells, the history of the wall charge for each discharge cell before the initializing discharge is erased, and wall charge required for a subsequent writing operation is formed. Discharge delay is reduced, and priming (detonating agent for discharge=exciting particle) for stably causing writing discharge is generated. In the writing time period, a scan pulse is sequentially applied to the scan electrodes, a writing pulse corresponding to an image signal to be displayed is applied to the data electrodes, writing discharge is selectively caused between the scan electrodes and the data electrodes, and the wall charge is selectively generated. In the subsequent sustaining time period, a predetermined number of sustaining pulses are applied between the scan electrodes and the sustain electrodes, and discharge and light emission are performed selectively in the discharge cells where the wall charge is generated by writing discharge.
For displaying an image correctly, it is important to certainly perform the selective writing discharge in the writing time period. However, the writing discharge has many factors that increase the discharge delay. The factors are, for example, facts that high voltage cannot be used for the writing pulses because of constraints in circuit configuration and that the phosphor layers formed on the data electrodes suppress the discharge. Therefore, the priming for stably causing the writing discharge becomes extremely important.
However, the priming generated by the discharge rapidly decreases with the passage of time. In the driving method of the panel, in the writing discharge after a lapse of a long time since the initializing discharge, the priming generated by the initializing discharge disadvantageously comes short, thereby increasing the discharge delay, destabilizing the writing operation, and reducing the image display quality. When the writing time period is set long for stabilizing the writing operation, disadvantageously, the time taken for the writing time period excessively increases.
For addressing the problems, a panel for generating the priming using a priming discharge cell disposed on the front plate of the panel and reducing the discharge delay, and a driving method of the panel are disclosed (for example, Japanese Patent Unexamined Publication No. 2002-150949).
In this panel, however, adjacent discharge cells are apt to interfere with each other. Especially, in the writing time period, the priming generated by writing discharge of the adjacent discharge cells can cause a writing error or bad writing, and hence the driving voltage margin of a writing operation becomes narrow.
The present invention addresses the problems, and provides a driving method of a plasma display panel capable of stably causing the writing discharge without reducing the driving voltage margin of the writing operation.